- Helix and Zoerkler collaborate on new architecture to improve efficiency in eVTOLs and unlock the future of flight
- New EPU combines Helix motor and Zoerkler transmission, reducing diameter by 50% compared to direct-drive system
- Provides over 100kW of lift power with up to 1,600Nm of torque
- 250kW of continuous power in cruise mode, with 400kW at peak loads
Milton Keynes, UK, [16 June 2026] – Helix, the UK manufacturer of the world’s most power-dense electric motors and inverters, has collaborated with high performance transmission specialist Zoerkler to develop and validate an industry-leading geared Electric Propulsion Unit (EPU) for advanced air mobility applications.
Designed to support demanding eVTOL applications, the new EPU can be installed to support propellers in lift, cruise, and tiltrotor configurations. Historically, these high-torque applications have required EPUs set out in a ‘direct drive’ layout, which demanded wider and higher-mass motors. Thanks to the seamless integration between Helix’s motor and Zoerkler’s lightweight transmission, however, this new EPU can deliver high torque in a package just 50% of the diameter of an equivalent direct drive unit.
Intended to be the first in a family of advanced air mobility EPUs, the initial Helix-Zoerkler collaboration has resulted in a 32.2kg package, which can deliver:
- 100kW of power with up to 1,600Nm of torque when used in a lift configuration
- 250kW of continuous power – and 400kW peak – when used in a cruise configuration
Thanks to Zoerkler’s transmission, which achieves 98% efficiency, the Helix motor within the EPU can be significantly narrower and lighter than a direct-drive alternative. This unlocks significant packaging opportunities for the EPU, with the initial unit having a diameter of just 26cm. Combined with the low mass of the package, this means the EPU can significantly reduce nacelle size and drag in eVTOL applications, enabling greater payloads and ranges.
Derek Jordanou-Bailey, Chief Engineer for Aerospace at Helix, said: “This new EPU shows that when brought together, best-in-class motors and transmissions can unlock a far lighter and more compact solution than direct drive systems. By combining the world-leading power density of Helix motors with Zoerkler’s lightweight and precise transmissions, this EPU provides advanced air mobility applications with a compact, low-mass solution that meets and even exceeds their range and payload requirements.”
Karl Lagler, Head of R&D at Zoerkler, said: “This collaboration demonstrates how combining advanced transmission technology with high-performance electric motors can redefine what is possible in eVTOL propulsion. By leveraging Zoerkler’s expertise in lightweight, high-efficiency gear systems, we have enabled a significantly more compact and scalable EPU architecture without compromising performance. This solution opens up new possibilities for aircraft designers to optimise space, weight, and overall system efficiency in next-generation air mobility platforms.”
Read our Advanced Air Mobility case study
About Zoerkler
Zoerkler is an Austrian specialist in high-performance transmission systems, delivering lightweight, highly efficient gear solutions for aerospace and advanced mobility applications. With decades of engineering expertise and a strong focus on precision, performance, and innovation, Zoerkler develops customised drivetrain solutions that meet the most demanding requirements in terms of efficiency, weight, and reliability. As part of the MiddleGround Capital Group alongside, Xtrac, New Eagle and Helix, Zoerkler combines global engineering excellence with local manufacturing know-how to support next-generation propulsion systems across aerospace and high-performance industries.
For further information, please visit zoerkler.at
